Which class of nondepolarizing muscle relaxants is associated with no significant histamine release?

Which class of nondepolarizing muscle relaxants is associated with no significant histamine release?

• A. Aminosteroid
• B. Benzylisoquinolinium
• C. Both classes release significant histamine
• D. No histamine release for all

Answer: (A)

Histamine release from nondepolarizing muscle relaxants can cause vasodilation, hypotension, flushing, and sometimes bronchospasm. Among these drugs, the benzylisoquinolinium group (for example, atracurium and cisatracurium) is the one most commonly associated with clinically significant histamine release. In contrast, the aminosteroid class (such as vecuronium, rocuronium, and pancuronium) generally does not provoke meaningful histamine release at typical clinical doses. Therefore, this class is the one associated with no significant histamine release, making it the best choice. The idea that all nondepolarizing relaxants release no histamine is incorrect, because benzylisoquinolinium agents can and do cause histamine release, and some agents can cause minor histamine effects in susceptible patients.

Histamine release from nondepolarizing muscle relaxants can cause vasodilation, hypotension, flushing, and sometimes bronchospasm. Among these drugs, the benzylisoquinolinium group (for example, atracurium and cisatracurium) is the one most commonly associated with clinically significant histamine release. In contrast, the aminosteroid class (such as vecuronium, rocuronium, and pancuronium) generally does not provoke meaningful histamine release at typical clinical doses. Therefore, this class is the one associated with no significant histamine release, making it the best choice. The idea that all nondepolarizing relaxants release no histamine is incorrect, because benzylisoquinolinium agents can and do cause histamine release, and some agents can cause minor histamine effects in susceptible patients.